The present invention relates to a dual plate friction clutch having an adjustable positioner and removable set clip for properly positioning an intermediate plate relative to a pair of driven discs.
Dual plate friction clutches having a pair of interleaved driven discs with an intermediate plate disposed between the driven discs are well-known in the prior art. Typically, a flywheel is attached to an input member with a clutch cover attached to the flywheel for rotation therewith. A pressure plate is disposed between the flywheel and the cover, and is connected to the cover for rotation therewith. The pressure plate is axially movable with respect to the cover between engaged and disengaged positions. The driven discs and intermediate plate are disposed between the flywheel and the pressure plate. The intermediate plate is connected to the cover for rotation therewith but may move axially relative to the cover. Rotational velocity is selectively transmitted from the flywheel to drive the driven discs via axial movement of the pressure plate and intermediate plate between respective disengaged and engaged positions.
The intermediate plate must be accurately positioned in order to provide proper clearance between the discs and the intermediate plate when the clutch is disengaged. Otherwise, there will be undesirable interaction between the intermediate plate and the driven discs. As a result, it is desirable to initially position the intermediate plate half way between the pressure plate and the flywheel in the disengaged position. Various arrangements have been used to properly position the intermediate plate.
In one system, a plurality of positioners are slidably mounted within apertures formed about the periphery of the intermediate plate. There is an interference fit between each positioner and the aperture resulting in a frictional resistance to motion. When the clutch is engaged, a forward end of each positioner abuts the rearward surface of the flywheel. When the clutch is disengaged, a rearward end of each positioner abuts the forward surface of the cover. As the facings of the intermediate plate and forward disc wear with use, the intermediate plate will be moved forwardly along the positioners towards the flywheel. This movement occurs because a force exerted on the intermediate plate with respect to the positioners when the clutch is engaged is greater than the frictional resistance between the positioners and the apertures of the intermediate plate.
In practice, proper positioning has been difficult to obtain with such systems. The clutch parts have manufacturing tolerances. As a result, when assembled, a positioner of a fixed axial length may resulted in undesirable interferences, particularly when the positioner is of insufficient length, resulting in improper positioning of the intermediate plate.